Valve mechanism for rock drills



Nov. 21, 1939 E TERRY 2.180564 VALVE MECHANISM F OR ROCK DRILLS Filed June 22, 193'.

NVENTOR.

48 J7 EdwardETfimy. 7 BY I 1 "2. H15 ATTORNEY Patented Nov. 21, 1939 7 UNlTED STATES PATENT orr cs s Q i N VALVE ivrnonnmi s fr iijn noon DRILL 7 Edward Terry, lhillipsburgl-N. J assignor to Ingersoll-Rand Company, Jersey City, N. J.,

a corporation of New Jersey Application Jute 22, 1937, Serial No. 149,554

. I 3 Claims. "This invention relates to rock dri1ls, and more particularly to a valve mechanism for roclr'd'rills of the fluid actuated type.

One object of the invention is to assure a rapid distribution of pressure fluid to the percussive element of the rock drill.

Another object is to provide a substantially directccurse for the pressure fluid flowing from supply to the percussive element.

Qtherobjects will bein part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts: j "Figures 1 and 2 are longitudinal elevations, in section, of so much of rock drills as will serve to illustrate the invention and showing the valve in the limiting positions.

Referring more particularly to the drawing, designates a rock drill comprising a cylinder 2| havinga piston chamber 22 to accommodate a reciprocatoryhammer piston 23. The piston controls a free exhaust port 2 land has a stem 25 slidable in a, front end closure 25, for the piston chamber, to deliver blows against the working implement-(not shown). I r v e The valve mechanism, designated in its entirety by 27, is arranged in the rear end .of the. cylinder 2! and comprises a valve chest 28 havin a recess 29 in its rearward extremity for the accommodation of rotation mechanism 30.

The rotation mechanism 30 may be conventional type consisting of a ratchetring 3| which encircles the head 32 of a rotation bar 33 extending through the valve chest 28 and intothe piston chamber 22. The head 32 carries thev usual spring-pressed pawls 3d for engagement with the teeth of theratchet ring 31, and in the rotation bar 33Vare spiral flutes 35 to engage ribs 36 carried by a nut 31 threaded into the piston23 to provide for relative rotary movement between the rotation bar and the piston.

The ratchet ring lies within the recess 29 and also extends into the front end of a back head 38 7 'to centralize the back head with respect to the .cylinder. The back head 38 forms the rearmost casing part of the rock drill. .It, seats directly upon the ratchet ring and may be clamped to the cylinder by any suitable means (notshown).

v The back head houses a'throttle valve 39 of the rotary type to control the admission of pressure fluid into the rock drill. The throttle valve has a central passage 46 which may be in constant communication with the source: of pressure fluid supply and in its Wall is a port 4| to register with a supply passage or passages 42 extending through the back head, the ratchet ring 3| and the valve chest to convey pressure fluid to the ,valve mechanism] I As a preferred form of construction the valve chest 23 comprises an outer annular member 44 and a plug 45 extending through the outer member 44 and cooperating therewith to define an annular valvechamber 45 for the accommodation of 'avalve 41 whereby the distribution of pressure fluid tothe piston chamber 22 iseifected. The rearmost end of the valve chamber 46 preferably lies adjacent the front terminus 10f the supply passage t2 and communicates therewiththrough a supply chamber 48 encircling the valve chamber 45,. Leading from a point forwardly of the supply chamber 48 and opening into the outer surface of the valve .chamber is an inlet passage 49 to, convey pressure fluid to the frontend of the piston chamber for driving the piston 23 rearwardly. e e

The pressure fluid ,employed for actuating the piston 23 on its working stroke also passes through the supply chamber 48 and in the present instance through therearward endof the valve chamber 46. The plug 45 is accordingly provided with an annular supply channel 50 located in the same transvers'e plane as the supply chamber 48 and opening into the inner surface of the valve chamber. The plug 45 is, moreover, provided with a series of inlet. passages 5! which lead from the supply channel 58 to an intermediate portion of the bore 52 in the plug through which the rotation bar extends.

The passages 5! preferably open directly into the flutes 35 of the rotation'bar so that pressure fluid employed for charging the rear end of the 'piston chamber will be'conveyed thereto by the ,flutes 35. However, if desired, additional flow area maybe provided between the passages 5| and the rearend of the .piston chamber by forming an enlarged portion-.53 in the part of the bore 52 extending from the passageslil to the piston chamber.

Communication 38 and the inlet passages 49' and 5! is controlled by a distributing valve 5 10f the sleeve type re cipiocable in the valve chamber 46. The valve has an internal flange 55 at itsfront endof which the outer end constitutes an actuating surface 56 which is intermittently subjected to pressure fluid for throwing the valve to its rearmost limiting position. The pressure fluid employed for this jpurpose is conveyed to the actuating surface 56 by a'passage 51 opening into the piston chamber between the supply chamber .waxq. stroke as the iston I01 throwing the valve 54 forwardly. The extreme rearward end of the valve constitutes a holding surface 60 against which pressure fluid flowing from the supply chamber 48 to the inlet passages 5| acts for holding the valve momentarily stationary in its foremost limiting position.

Communication between the supply chamber 48 and the inlet passage 49 is afforded by an annular groove 6| in the periphery of the valve 54. The groove BI is of such length that, in the rearmost limiting position of the valve, it establishes communication between the supply passage .48 and the inlet passage 49 and in the foremost limiting position it communicates the inlet passage 49 with an atmospheric vent 62 in the valve chamber to provide an escape for air expelled from the front end of the piston chamber 22 during the working stroke of the piston so that its .force will not be diminished by compression.

The operation of the device is as follows: With the valve in its foremost limiting position in the valve chamber and the piston in position to begin its working stroke, as illustrated in Figure 1, pressure fluid flows from the supply chamber {across the rear end of the valve into the supply channel 50, thence through the inlet passage or passages 5| and the flutes 35 into the rear end of the piston chamber 22 and drives the piston 23 forwardly.

During its course through the rear end of the valve chamber 46 the pressurefluid acts against the holding surface 60 and maintains the valve in the position described until the piston 23 uncovers the passage 51. Pressure fluid then flows from the rear end of the piston chamber through the passage 51 against the actuating surface 56 and moves the valve 54 rearwardly and holds it in that position.

When the piston 23 uncovers the exhaust port 24 the pressure fluid in the rear end of the piston chamber and that acting against the actuating surface 56 is exhausted to the atmosphere. However, during the forward stroke of the piston and after it covers the free exhaust port 24 the air in the front end of the piston chamber 22 is expelled through the passage 49, the groove 6! in the valve and the atmospheric vent 62, so that the piston will be unhamp'ered by compression in the front end of the piston chamber and may, therefore, deliver a powerful blow against the working implement.

In the new position of the valve the groove 6| establishes communication between the supply chamber 48 and the inlet passage 59. Pressure fluid then flows from the supply chamber through the inlet passage 49 to the front end of the piston chamber and drives the piston rearwardly. During this movement of the piston, and after it covers the exhaust port, the air compressed in the rear end of the piston chamber flows through the flutes 35, the passages 5| and the supply channel 50 against the actuating surface 59 and throws the valve forwardly to its initial position. The pressure fluid employed for driving the piston rearwardly is then exhausted through the port 24, and upon shifting of the valve forwardly pressure fluid again flows from the supply chamber 48 through the inlet passages 5i and the flutes 35 to start a new cycle of operations.

In practice the present invention has been found to be highly advantageous in devices of the character to which it pertains. Owing to the arrangement of the supply chamber and the inlet passages and the manner in which the com- ;munioate with each other the pressure fluid flowing from supply will follow practically a direct course to the ends of the piston chamber. This is desirable since it eliminates the power losses known to occur at deflection points. Another advantage of the present invention is that by conveying the pressure fluid through the flutes 35 to the rear end of the piston chamber the entrained lubricant will be deposited upon the surfaces of the flutes and those of the piston cooperating with them so that these elements will at all times be adequately lubricated.

I claim:

1. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston therein, a valve chest comprising an outer member and a plug extending through the outer member and cooperating therewith to define a valve chamber, a supply chamber in the outer member opening into the rearward end of the valve chamber, an inlet passage opening into the outer surface of the valve chamber forwardly of the supply chamber and leading to the front end of the piston chamber, an inlet passage in the plug opening into the rearward end of the valve chamber in the same transverse plane as the supply chamber andleading to the rear end of the piston chamber, a valve in the valve chamber to control communication between the supply chamber and the inlet passages, and actuating surfaces on the valve subjected to fluid under pressure for throwing the valve.

2. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston therein, a valve chest at .the rear end of the piston chamber comp-rising an outer member and a plug extending through the outer member and cooperating therewith to define an annular valve chamber, an annular supply chamber in the outer member encircling the valve chamber and opening into the rearward end thereof, an

annular supply channel in the plug in the same transverse plane as the supply chamber and opening into the rearward end of the valve chamber, inlet passages in the plug leading from the supply channel to the rear end of the piston chamber, an inlet passage opening into the outer surface of the valve chamber forwardly of the supply chamber and leading to the front end of the piston chamber, a valve in the valve chamber to control communication between the supply chamber and the front inlet passage and between the supply chamber and the supply channel, an actuating surface on the valve subjected to compression for throwing the valve in one direction, and an opposed actuating surface subjected to pressure fluid valved by the piston for throwing the valve in the opposite direction.

3. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston therein, a valve chest at one end of the piston chamber having an annular valve chamber and a bore, a rotation bar extending through 7 the bore, a supply chamber, an inlet passage leadpiston chamber, a valve in the valve chamber to ing from theouter surface of the valve chamber control communication between the supply cham- ;to the front end of the piston chamber, an inlet ber and the inlet passages, and actuating surpassage leadingfifrom the inner surface of the faces on the valve subjected to fluid under pres- 5 valve chamber .tqj the bore, flutes in the rotation sure for throwing the valve.

bar to convey pfifessure fluid from the last-mentioned inletpassage into the rear end of the EDWARD F; TERRY. 

